As known from the prior art, on the floor of the basement space situated underneath the dryer section of a paper machine, a broke conveyor is placed and functions to receive the paper web that falls down from the dryer section, in the event of a web break, and carry the same into a pulper. Thus, the provisions for the paper that falls down from the dryer section onto the broke conveyor occupy the entire basement space so that no other equipment can be placed there. The inability to place other equipment in the basement spaces is also restricted by the fact that the basement spaces are moist and hot spaces. As known from the prior art, the basement space is a substantially integral space with the interior of the hood placed on the dryer section above the floor level of the paper machine hall. As such, in the basement space, substantially the same moist and hot atmosphere is present as in the interior of the hood. As is also known from the prior art, the basement space is provided with a so-called basement hood by whose means, together with the hood placed above the floor level, the moist and hot spaces of the dryer section are isolated from the paper machine hall and from the rest of the environment. In a manner in itself known to those skilled in the art, the hood spaces are provided with means for air conditioning and recovery of heat.
The prior art basement space placed underneath the dryer section is, with the exception of the removal of the paper broke, primarily unused lost space, which must, moreover, be provided with the basement hood. Typically, the dimensions of the basement space are about 5 m.times.10 m.times.80 m or about 4000 cubic meters.
In a manner known in the prior art, when groups with twin-wire draw are used in the dryer section, a part of the top portion of the basement space is used for the runs of the loops of the lower drying wires and for the guide rolls. In recent years though, increasing use has been made of single-wire draw and, in connection with it, of so-called normal groups, in which the drying cylinders are placed in the upper row and the reversing suction rolls or cylinders in the lower row, in which case the loops of the drying wires run above the dryer groups. In such a case, an increased proportion of useless, lost space remains in the basement space.
Conventionally, to construct a dryer section, one manufacturer supplies the dryer section of the paper machine, and some other supplier constructs the basement space placed underneath, in which case the overall solution does not always become optimal in every respect.